Error reduction of depth maps

ABSTRACT

The described implementations relate to reducing distance errors in depth maps. One example can detect blooming in a depth map. This example can identify a depth range affected by the blooming and take an action relating to the identified depth range to address the blooming.

BACKGROUND

Depth maps provide useful information in many scenarios, such asindustrial settings, transportation, gaming, augmented reality, etc.Depth maps can be generated based in part upon light reflected fromobjects in a scene. In some instances, highly reflective objects in thescene can reflect so much light that sensors gathering the reflectedlight are overwhelmed. This occurrence can cause erroneous depthdistances to be calculated for these highly reflective objects. Evenmore troublesome is that this occurrence can also cause erroneous depthdistances to be calculated for other objects in the scene. The presentconcepts can reduce these erroneous distances in the depth map.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings illustrate implementations of the conceptsconveyed in the present patent. Features of the illustratedimplementations can be more readily understood by reference to thefollowing description taken in conjunction with the accompanyingdrawings. Like reference numbers in the various drawings are usedwherever feasible to indicate like elements. Further, the left-mostnumeral of each reference number conveys the figure and associateddiscussion where the reference number is first introduced.

FIGS. 1A-1G and 2A-2C show example depth map scenarios in accordancewith some implementations of the present concepts.

FIG. 3 shows an example bloom detection technique in accordance withsome implementations of the present concepts.

FIGS. 4 and 5 show example flowcharts for accomplishing bloom detectionand reduction concepts in accordance with some implementations.

FIG. 6 shows an example system for accomplishing the present bloomreduction concepts.

DETAILED DESCRIPTION

This discussion relates to depth maps. A depth map can show a scene andindicate distances to items in the scene, such as on a pixel-by-pixelbasis, a per region basis, and/or a per object basis. Various factorscan induce errors in the indicated distances. One such factor isblooming. Briefly, blooming can be viewed as an instance where a stronglight signal from one region of the depth image bleeds into adjacentregions (e.g., creates blooming artefacts) so that erroneous distancesare determined for the adjacent regions. Stated another way, a bloomingartefact can be caused by reflections from one region that overflow intoadjacent regions and create artefacts in those adjacent regions thatcause the depths calculated for those regions to be erroneous. Thepresent concepts can recognize blooming in the depth image and identifya depth range affected by the blooming. Various actions can be taken toaddress the blooming. From one perspective, blooming is a technicalproblem that causes inaccuracies in depth maps. The describedimplementations can provide a technical solution that reduces theseblooming related inaccuracies.

FIGS. 1A-1G collectively show an example scene 100 that includes objects102. In this example, scene 100 is a construction zone and the objectsinclude a person or worker 104 (FIG. 1C) who is walking in theconstruction zone among posts 106. A depth camera 108 can sense depthdata from the scene 100. For instance, the depth camera 108 can sensereflections off objects 102 in the scene and determine distances tothose objects. Any type of depth camera can be employed, such as atime-of-flight depth camera, stereo depth camera, and/or structuredlight depth camera, among others.

FIG. 1A shows scene 100 at a first instance. FIG. 1B shows a depth map110 of scene 100 at the first instance as sensed by depth camera (108,FIG. 1A). (Note that the depth map is simplified to accommodate thelimitations of line drawings). The depth map 110 shows distances to theobjects 102 from the depth camera. For instance, the depth map shows thedistance to post 106(1) is 1 meter, the distance to post 106(2) is 3meters, the distance to post 106(3) is 6 meters, and the distance topost 106(4) is 8 meters. (Note in this representation, one distance isassigned to each object. Other implementations may include greaterlevels of detail, up to and including a distance per pixel.)

FIG. 1C shows scene 100 at a second instance where person 104 hasentered the scene. In this example, the person 104 is wearing a highlyreflective object 112 in the form of a reflective safety vest 114.Highly reflective objects 112 can detrimentally affect the accuracy of adepth map of the scene.

FIG. 1D shows an expected depth map 110A for the second instance. Thisexpected depth map 110A shows the person 104 to be about the samedistance from the depth camera as post 106(2) (e.g., about 3 meters).However, recall that highly reflective objects 112 can cause problemsfor the depth camera.

FIG. 1E shows an actual depth map 1108 for the second instance. In thiscase, the reflective safety vest 114 causes aberrations in depth map1108. These aberrations can be viewed as a blooming effect 116. Theblooming effect 116 can be caused when such a strong reflective signalis returned from the highly reflective object 112 that the strongreflective signal overwhelms reflective signals of other objects 102that are aligned in proximity to the highly reflective object (from theperspective of the depth camera 108). In this example, the objects thatare aligned in proximity to the highly reflective object 112 are posts106(3) and 106(4). Note, that the blooming effect 116 is so strong onthe depth camera, that in the depth map 1108, posts 106(3) and 106(4)are indicated as the same distance as the person (e.g., 3 meters) ratherthan their actual distances of 6 and 8 meters, respectively.

FIG. 1F shows a first way that the blooming effect 116 can be addressed.In this case, all objects 102 that appear on the depth map 110C to be atthe distance of the blooming effect are assigned a distance of ‘null’ or‘not available’. Thus, in this case, the person 104, posts 106(2),106(3) and 106(4) are all indicated at 3 meters and these distances arereplaced by null values.

FIG. 1G shows an alternative solution to the blooming effect 116. Inthis case, all objects 102 that appear on the depth map 110D to be atthe distance of the blooming effect 116 and are adjacent to the bloomingeffect are assigned a distance of null or not available. In this case,the person 104, posts 106(2), 106(3) and 106(4) are all indicated at 3meters. However, post 106(2) is not adjacent to the blooming effect 116.Thus, post 106(2) retains its 3-meter value while distances for person104 and posts 106(3) and 106(4) are replaced by null values. Thissolution recognizes that while post 106(2) has the same distance valueas the blooming effect 116, the distance calculated for this post is notlikely affected by the blooming effect of the highly reflective object112.

FIGS. 2A-2C collectively show another scene 100E. (The suffix ‘E’ isused to distinguish this scene from the scenes discussed relative toFIGS. 1A-1G and to convey that the elements of scene 100E may bedifferent than those of FIGS. 1A-1G. Suffixes ‘A’-‘D’ were used in thediscussion above).

As shown in FIG. 2A, scene 100E involves objects 102 in the form of atable 202, a chair 204, and a desk 206. Positioned on the desk 206 are adepth camera 108, a display 208, and a computer 210. The depth camera108 is positioned on a surface 212 of the desk 206 and is facing towardthe table 202 and the chair 204. In this case, the surface 212 acts as ahighly reflective object 112 relative to the depth camera 108. Assumefor purposes of explanation, that depth camera 108 and computer 210 areconnected to display 208. Assume further that chair 204 is 2 meters infront of the depth camera 108 and table 202 is 4 meters in front of thedepth camera.

FIG. 2B shows an expected depth map 214 on display 208 of the scene 100Eas sensed by the depth camera 108. As mentioned above, the expecteddistance to the chair 204 is 2 meters and to the table is 4 meters.

FIG. 2C shows an actual depth map 216 of the scene 100E as sensed by thedepth camera 108. In this case, blooming effect 116 occurs when lightsignals emitted by depth camera 108 reflect off of the surface 212. Thisreflection from the surface 212 is so strong that it overwhelms signalsreturning from the chair 204, which is adjacent to the surface 212 inthe line of sight of the depth camera. The overwhelming reflectedsignals from the surface 212 cause the distance to the chair 204 to becalculated as the distance to the surface (e.g., 0.01 meters) instead ofthe expected 2 meters. The blooming effect 116 does not affect areas ofthe depth camera's sensor receiving reflections from the table 202.Thus, the depth camera can calculate an accurate distance to the table202 (e.g., the determined distance generally matches the actual orexpected distance).

The present concepts can be employed to recognize the blooming effect116. Once recognized, actions can be taken to diminish ramifications ofthe blooming effect. For instance, distances of objects 102 that areaffected can be treated as suspicious. As described above relative tothe discussion of FIGS. 1A-1G, the distances affected by the bloomingeffect can be invalidated, among other actions. Note that if notinvalidated, the bloom affected pixels would have catastrophically falsedepth values (e.g., the distance to the surface of the table rather thanthe distance to the chair). This would likely severely impact customersof the depth maps, such as surface reconstruction applications, amongothers.

FIG. 3 shows a technique 300 that can recognize blooming effects andgenerate a revised depth map 302. This technique can receive the actualdepth map 216 and a corresponding active brightness image or activebrightness map 304. The active brightness image 304 can be a product ofthe depth determination process. For instance, when the depth map 302 isdetermined by time-of-flight techniques (e.g., time-of-flight depthmap), the active brightness image 304 can also be output.

The active brightness image 304 can show brightness levels of individualregions and/or pixels of the depth camera's sensors. The brightnesslevel can be indicated as a percentage value, such as from 0% to 100% oras an absolute value. For instance, an 8-bit binary includes 256brightness values (e.g., 0-255). In the illustrated example, pixels306(1) relating to the table 202 are at 70% percent brightness, forinstance, while pixels 306(2) that include the chair 204 are at 100%brightness (e.g., are saturated). In this technique, the saturatedpixels are suspected of having erroneous depth values.

Actual depth map 216 and active brightness image 304 can be combined togenerate revised depth map 302. The revised depth map indicates that thechair 204 is located within the region of saturated pixels 306(2) (e.g.,group of adjacent saturated pixels). As such, the mapped distance of thechair 204 is likely erroneous. Accordingly, the distance of the chair inthe revised depth map is indicated as not available (NA). Thus, in therevised depth map 302, pixels that were indicated in the actual depthmap 216 to be valid, but that are associated with the blooming effect,can be indicated as invalid in the revised depth map.

FIG. 4 shows another example bloom reduction method or technique 400.Block 402 can receive a depth map of a scene. The depth map can beproduced utilizing various techniques, such as structured light, stereoimagery, light detection and ranging (LIDAR), and/or time of flight,among others. The depth map may include pixel brightness information,such as a reserved saturated pixel code, and/or be associated with acorresponding active brightness image that conveys pixel brightnessinformation, among other techniques.

Block 404 can attempt to detect blooming in the depth map. In someimplementations, the blooming can be detected by analyzing saturatedpixels in the depth map. For instance, groups of adjacent saturatedpixels can be indicative of blooming. Note, in some implementations thebloom detection can be achieved with relatively low resource usage. Forinstance, the depth map's active brightness image can be checked forsaturated pixels. In another case, pixel brightness information can bestored with the depth map. This pixel brightness information can beaccessed and utilized to identify saturated pixels. If no (or less thana threshold number of) saturated pixels are identified, no furtherresources need be utilized.

If no blooming is detected, the method can await the next depth map. Thedetermination regarding blooming can be a binary determination (e.g.,yes/no) or can be associated with a probability (e.g., 60%) thatblooming occurred. This latter determination can be followed by nuancedactions to reduce effects of the blooming. For instance, if the depthmap includes a small group of saturated pixels, there may be lessconfidence that blooming occurred. Thus, an appropriate response may beto simply void those pixels rather than inferring an effect ontoadjacent pixels.

If blooming is detected, block 406 can identify pixels of the depth mapaffected by the blooming. The identified pixels can be all saturatedpixels. Alternatively, the identified pixels can be groups of adjacentpixels (e.g., at least 1000 adjacent pixels that are all saturated). Inthis latter solution, not all pixels that are saturated are treated asbeing affected by blooming. In still another implementation, a distancecan be determined for the blooming. For instance, in the example ofFIGS. 1A-1G, the blooming effect is at 3 meters. Thus, all pixels thatare recorded at 3 meters could be treated as being affected by theblooming. Alternatively, only those pixels at 3 meters that arecontiguous with the blooming effect are treated as being affected.

Block 408 can then take an action on the pixels to reduce effects of theblooming. The action could be attempting to correct the distance of thepixels affected by the blooming. Another action could be associating anotation with the values of the pixels that the distances may not bereliable. Another action could be to invalidate the distances andsubstitute a value of ‘void’ or ‘not available.’

Note that in some implementations the action can be taken relative toall pixels that have the depth associated with blooming. For instance,looking at FIG. 1E, saturated pixels are identified relative to person104 and posts 106(3) and 106(4). Further, person 104 and posts 106(2),106(3), and 106(4) are all indicated at 3 meters. Thus, pixelsassociated with all of these objects could be invalidated as shown inFIG. 1F. Alternatively, only pixels that are adjacent may be treated asbeing affected. In this case, the pixels associated with person 104 andposts 106(3) and 106(4) are adjacent, whereas they are spaced away frompixels associated with post 106(2). Thus, as shown in FIG. 1G, distancesof pixels associated with person 104 and posts 106(3) and 106(4) (e.g.,in the region of blooming effect 116) may be invalidated while thedistances of pixels of post 106(2) may be maintained.

In one case, the action at block 408 can entail generating another depthmap in which pixels affected by the blooming, such as those falling intoa depth range associated with the blooming, are invalidated. Forinstance, the new (e.g., another or revised) depth map can be identicalto the original depth map except that a subset of pixels that had validdepth readings in the original depth map have invalid ‘null’ readings inthe new depth map. The subset of pixels may be limited to the saturatedpixels. Alternatively, the subset of pixels may include saturated pixelsand unsaturated pixels.

FIG. 5 shows another example bloom reduction method or technique 500.Block 502 can receive a depth map of a scene and a corresponding activebrightness image of the scene. For instance, when time-of-flighttechniques are used to generate the depth map, the active brightnessimage can be generated as a result of processing sensor data to producethe depth map.

Block 504 can determine whether blooming affected the depth map. In someimplementations, the determination can be accomplished by counting thenumber of pixels that are saturated in the active brightness image. Some3D cameras automatically mark saturated pixels with a special label. Ifthe camera employed does not include this feature, the active brightnessvalue of a pixel can be compared to a predefined active brightnessthreshold. The pixel can be declared saturated if the pixel's activebrightness value exceeds the threshold. Thus, a determination can bemade whether individual pixels are saturated and then a determinationcan be made regarding the total number of saturated pixels in the activebrightness image.

If the number of saturated pixels exceeds a saturation threshold thenthe determination can indicate blooming occurred. For instance, thesaturation threshold could be set at 1% of the total number of pixels inthe active brightness image. If the saturation threshold is exceeded,blooming is detected (e.g., ‘yes’ at 504) and the method proceeds toblock 506, otherwise, the method awaits the next depth map.

Block 506 can identify a depth range of the saturated pixels. Forinstance, the depth range can be determined by comparing, such asoverlaying, the depth map and the active brightness image (see forinstance, FIG. 3). In that example, the depth range (from the actualdepth map 216) that contains the saturated pixels (306(2) from theactive brightness image 304) is 0.01 meters. Thus, the depth range ofthe saturated pixels is 0.01. Note that while a specific depth value isshown here, the depth value may be a range, such as 0.008 meters to0.012 meters for instance. Note also, that a scene could have more thanone highly reflective object 112. For instance, the person from FIGS.1A-1G could stand next to the table 202 in FIGS. 2A-2C. In such a case,there could be a range of saturated pixels cause by the surface 212 ofthe desk at 0.01 meters and a second range at 4 meters from the person'sreflective safety vest 114.

Block 508 can invalidate the depth range of the saturated pixels fromthe depth map. The action can be taken relative to all pixels at thedepth range or a sub-set of those pixels. For instance, a group ofadjacent pixels may be saturated and may represent a blooming effect.However, another pixel or pixels may be saturated, but may not bealigned with the group of pixels (e.g., not aligned with the group ofpixels in a line of sight of the sensors). This pixel or pixels may notbe affected by blooming.

Block 510 can generate another depth map that includes invalidateddepths for the saturated pixels. Various examples are described abovewhere the values of the saturated pixels are revised to ‘null’ in theanother (e.g., revised) depth map.

One example implementation that is consistent with method 500 is nowdiscussed in detail. This method is explained relative to time-of-flighttechnology, and is applicable to other technologies. Time-of-flight andstructured light technologies, generally employ infrared (IR) light thatis invisible to the user. Recall that blooming typically occurs if thereis an object (e.g., a highly reflective object) in the scene thatreflects a very high amount of light (in this case IR light). Thetypical blooming artefact is that the depth of this highly reflectiveobject overwrites the depth values of other pixels that capture objectsreturning a lower amount of light (see FIG. 1E). Therefore, theimplementation can identify the depth value of the object causing theblooming, and then invalidate pixels that are assigned to thisparticular depth value.

The implementation can compute the set of all valid depth pixels thathave a spatial neighbor that is saturated. For instance, spatialneighbors can be defined as 8-connected pixels. 8-connected pixels areneighbors to every pixel that touches one or their edges or corners.This set of pixels can be referred to the transition zone set. Fromanother perspective, the method can identify saturated pixels and pixelsthat are adjacent to saturated pixels.

The implementation can generate a histogram of depth values for thetransition zone set. Each bin of the histogram can capture a depthrange. For instance, in one example the histogram can include 1400 binsand each bin in the histogram can capture a depth range of 5 mm. Thus,this example histogram can capture a total depth range between 0 mm and5*1400=7000 mm. This implementation can insert the depth of each pixelof the transition zone set into the histogram. For example, if a pixelof the transition zone set has a depth value of 3000 mm, theimplementation can add a count of 1 to the 3000/5=600th bin of thishistogram.

Some versions can apply histogram smoothing to fill in gaps in thehistogram. This smoothing can be accomplished by replacing every bin'svalue with an average value. This average can be computed over thecurrent bin's value as well as its adjacent neighboring bins (e.g., itstwo left and its two right neighboring bins, for example).

The implementation can estimate a depth range affected by the blooming[Dmin, Dmax]. The estimate can be more robust based upon the smoothingperformed above. The estimate can be generated by computing the largestsequence of consecutive bins in the smoothed histogram where each bin ofthat sequence has a count larger than 0. Note that this method canassume that there is only one object causing blooming in the scene. Asmentioned above, there could be multiple highly reflective objects inthe scene causing multiple blooming effects (e.g., a first distancerange affected by a first bloom and a second distance range affected bya second bloom). The estimate can be extended to two objects bycomputing the largest two sequences in the smoothed histogram.

The implementation can now generate the final depth map by traversingall pixels of the original depth map. If the depth value of a pixel doesnot fall within the interval [Dmin, Dmax], the pixel's depth value canbe copied to the final depth map. Conversely, if the pixel's depth valuefalls into the depth interval, the pixel can be invalidated in the finaldepth map.

An alternative bloom reduction method is described below. This methodtakes advantage of the shape of the depth camera's illumination pattern.This particular implementation is described relative to a depth camerathat creates a depth map that includes an illumination pattern, such asa has a hexagonal shape. The unilluminated parts of the depth map (e.g.,those outside the illumination pattern) can provide useful information,as they should have an active brightness very close to 0. If they donot, this is likely due to blooming. Hence the unilluminated regions ofthe image can provide a direct reading of the blooming signal. Since thesignal added by blooming can be directly observed in the unilluminatedregions, this signal can be subtracted from the observed signal. Theresulting corrected/revised depth map can have reduced blooming effects.

FIG. 6 shows a system 600 that can accomplish bloom reduction concepts.For purposes of explanation, system 600 can include four devices 602(1),602(2), 602(3), and 602(4). Device 602(1) is manifest as a depth camerathat is similar to depth camera 108 of FIG. 1A. Device 602(2) ismanifest as a head mounted augmented reality device, and device 602(3)is manifest as a tablet-type device. Any of these devices can befree-standing and/or can communicate with other devices, such asserver-type devices 602(4). Individual devices 602 can include anemitter 604, optics 606, sensor 608, controller 610, a bloom reductioncomputation component 612, a processor 614, and/or storage 616.

FIG. 6 shows two device configurations 618 that can be employed bydevices 602. Individual devices 602 can employ either of configurations618(1) or 618(2), or an alternate configuration. (Due to spaceconstraints on the drawing page, one instance of each deviceconfiguration is illustrated rather than illustrating the deviceconfigurations relative to each device 602). Briefly, deviceconfiguration 618(1) represents an operating system (OS) centricconfiguration. Device configuration 618(2) represents a system on a chip(SOC) configuration. Device configuration 618(1) is organized into oneor more applications 620, operating system 622, and hardware 624. Deviceconfiguration 618(2) is organized into shared resources 626, dedicatedresources 628, and an interface 630 therebetween.

In some implementations, the emitter 604 emits light, such as IR light.The optics 606 receive reflected light from the scene and focus thereflected light on sensor 608. The controller 610 can coordinate thefunction of the emitter 604 and sensor 608. The bloom reductioncomputation component 612 can generate depth maps by analyzing theemitted light and the sensed reflected light. The bloom reductioncomputation component 612 can analyze the depth maps to detect blooming,identify a depth range affected by the blooming, and/or take an actionrelating to the depth range.

In some configurations, each of devices 602 can have an instance of thebloom reduction computation component 612. However, the functionalitiesthat can be performed by bloom reduction computation component 612 maybe the same or they may be different from one another. For instance, insome cases, each device's bloom reduction computation component 612 canbe robust and provide all of the functionality described above and below(e.g., a device-centric implementation). In other cases, some devicescan employ a less robust instance of the bloom reduction computationcomponent 612 that relies on some functionality to be performed byanother device. For instance, device 602(4) may have more processingresources than device 602(1). In such a configuration, some bloomreduction computation component functions may be performed on device602(4) rather than device 602(1).

The term “device,” “computer,” or “computing device” as used herein canmean any type of device that has some amount of processing capabilityand/or storage capability. Processing capability can be provided by oneor more processors that can execute data in the form ofcomputer-readable instructions to provide a functionality. Data, such ascomputer-readable instructions and/or user-related data, can be storedon storage, such as storage that can be internal or external to thedevice. The storage can include any one or more of volatile ornon-volatile memory, hard drives, flash storage devices, and/or opticalstorage devices (e.g., CDs, DVDs etc.), remote storage (e.g.,cloud-based storage), among others. As used herein, the term“computer-readable media” can include signals. In contrast, the term“computer-readable storage media” excludes signals. Computer-readablestorage media includes “computer-readable storage devices.” Examples ofcomputer-readable storage devices include volatile storage media, suchas RAM, and non-volatile storage media, such as hard drives, opticaldiscs, and flash memory, among others.

Examples of devices 602 can include traditional computing devices, suchas personal computers, desktop computers, servers, notebook computers,vehicles, smart cameras, surveillance devices/systems, safetydevices/systems, wearable smart devices, appliances, and otherdeveloping and/or yet to be developed device types, etc.

As mentioned above, device configuration 618(2) can be thought of as asystem on a chip (SOC) type design. In such a case, functionalityprovided by the device can be integrated on a single SOC or multiplecoupled SOCs. One or more processors 614 can be configured to coordinatewith shared resources 626, such as memory/storage 616, etc., and/or oneor more dedicated resources 628, such as hardware blocks configured toperform certain specific functionality. Thus, the term “processor” asused herein can also refer to central processing units (CPUs), graphicalprocessing units (GPUs), field programmable gate arrays (FPGAs),controllers, microcontrollers, processor cores, or other types ofprocessing devices.

Generally, any of the functions described herein can be implementedusing software, firmware, hardware (e.g., fixed-logic circuitry), or acombination of these implementations. The term “component” as usedherein generally represents software, firmware, hardware, whole devicesor networks, or a combination thereof. In the case of a softwareimplementation, for instance, these may represent program code thatperforms specified tasks when executed on a processor (e.g., CPU orCPUs). The program code can be stored in one or more computer-readablememory devices, such as computer-readable storage media. The featuresand techniques of the component are platform-independent, meaning thatthey may be implemented on a variety of commercial computing platformshaving a variety of processing configurations.

Various examples are described above. Additional examples are describedbelow. One example includes a method comprising receiving a depth map ofa scene and a corresponding active brightness image of the scene,detecting blooming in the depth map at least in part from saturatedpixels in the active brightness image, identifying a depth range of thesaturated pixels, invalidating the depth range of the saturated pixelsfrom the depth map, and generating another depth map that includesinvalidated depths for the saturated pixels.

Another example can include any of the above and/or below examples wherethe receiving comprises receiving the depth map from a time-of-flightcamera.

Another example can include any of the above and/or below examples wherethe invalidating the depth range of the saturated pixels comprisesinvalidating only saturated pixels.

Another example can include any of the above and/or below examples wherethe invalidating the depth range of the saturated pixels comprisesinvalidating saturated pixels and unsaturated pixels.

Another example can include any of the above and/or below examples wherethe detecting blooming in the depth map comprises making a binarydetermination whether blooming occurs in the depth map.

Another example can include any of the above and/or below examples wherethe making a binary determination is based at least in part upon anumber of saturated pixels in the active brightness image.

Another example can include any of the above and/or below examples wherethe making a binary determination is based at least in part upon anumber of saturated pixels in the active brightness image that areadjacent to one another.

Another example can include any of the above and/or below examples wherethe detecting comprises computing a set of all valid depth pixels thathave a spatial neighbor that is saturated.

Another example can include any of the above and/or below examples wherethe identifying comprises generating a histogram of depth values for theset.

Another example can include any of the above and/or below examples wherethe method further comprises smoothing the histogram.

Another example can include any of the above and/or below examples wherethe smoothing comprises replacing a value of individual bins of thehistogram with an average value.

Another example can include any of the above and/or below examples wherethe replacing comprises calculating the average value as the value of anindividual bin averaged with at least two adjacent neighboring bins.

Another example includes a system comprising a depth camera configuredto capture a depth map of a scene and a processor configured to: detectblooming in the depth map, identify a depth range affected by theblooming, and take action relating to the depth range.

Another example can include any of the above and/or below examples wherethe depth camera and the processor are implemented on a single device.

Another example can include any of the above and/or below examples wherethe depth camera is manifest on a first device and the processor isimplemented on a second device.

Another example can include any of the above and/or below examples wherethe processor is configured to identify the depth range by identifyingsaturated pixels and adjacent pixels of the depth map.

Another example can include any of the above and/or below examples wherethe processor is configured to take the action where the action isinvalidating the depth range.

Another example can include any of the above and/or below examples wherethe processor is configured to perform the invalidating only on regionsof the depth range that are aligned with saturated pixels in an activebrightness image that corresponds to the depth map.

Another example can include any of the above and/or below examples wherethe depth camera is configured to store pixel brightness informationwith the depth map and the processor is configured to detect theblooming at least in part from the pixel brightness information, orwherein the depth camera is configured to generate an active brightnessimage that corresponds to the depth map and the processor is configuredto detect the blooming at least in part from the active brightnessimage.

Another example includes a device comprising a depth camera configuredto generate a depth map of a scene and a bloom reduction computationcomponent configured to detect blooming in the depth map, identifypixels of the depth map affected by the blooming, and, take an action onthe pixels to reduce effects of the blooming.

CONCLUSION

The order in which the disclosed methods are described is not intendedto be construed as a limitation, and any number of the described blockscan be combined in any order to implement the method, or an alternatemethod. Furthermore, the methods can be implemented in any suitablehardware, software, firmware, or combination thereof, such that acomputing device can implement the method. In one case, the methods arestored on one or more computer-readable storage media as a set ofinstructions such that execution by a processor of a computing devicecauses the computing device to perform the method.

Although techniques, methods, devices, systems, etc., pertaining tobloom reduction are described in language specific to structuralfeatures and/or methodological acts, it is to be understood that thesubject matter defined in the appended claims is not necessarily limitedto the specific features or acts described. Rather, the specificfeatures and acts are disclosed as example forms of implementing theclaimed methods, devices, systems, etc.

The invention claimed is:
 1. A method, comprising: receiving a depth mapof a scene and a corresponding active brightness image of the scene;detecting blooming in the depth map at least in part from saturatedpixels in the active brightness image; identifying a depth range of thesaturated pixels; invalidating the depth range of the saturated pixelsfrom the depth map; and, generating another depth map that includesinvalidated depths for the saturated pixels.
 2. The method of claim 1,wherein the receiving comprises receiving the depth map from atime-of-flight camera.
 3. The method of claim 1, wherein theinvalidating the depth range of the saturated pixels comprisesinvalidating only saturated pixels.
 4. The method of claim 1, whereinthe invalidating the depth range of the saturated pixels comprisesinvalidating saturated pixels and unsaturated pixels.
 5. The method ofclaim 1, wherein the detecting blooming in the depth map comprisesmaking a binary determination whether blooming occurs in the depth map.6. The method of claim 5, wherein the making a binary determination isbased at least in part upon a number of saturated pixels in the activebrightness image.
 7. The method of claim 6, wherein the making a binarydetermination is based at least in part upon a number of saturatedpixels in the active brightness image that are adjacent to one another.8. The method of claim 1, wherein the detecting comprises computing aset of all valid depth pixels that have a spatial neighbor that issaturated.
 9. The method of claim 8, wherein the identifying comprisesgenerating a histogram of depth values for the set.
 10. The method ofclaim 9, further comprising smoothing the histogram.
 11. The method ofclaim 10, wherein the smoothing comprises replacing a value ofindividual bins of the histogram with an average value.
 12. The methodof claim 11, wherein the replacing comprises calculating the averagevalue as the value of an individual bin averaged with at least twoadjacent neighboring bins.
 13. A system, comprising: a depth cameraconfigured to capture a depth map and a corresponding active brightnessimage of a scene; and, a processor configured to: detect blooming in thedepth map at least in part from saturated pixels in the activebrightness image, identify a depth range of the saturated pixels,invalidate the depth range of the saturated pixels from the depth map,and generate another depth map that includes invalidated depths for thedepth range.
 14. The system of claim 13, wherein the depth camera andthe processor are implemented on a single device.
 15. The system ofclaim 13, wherein the depth camera is manifest on a first device and theprocessor is implemented on a second device.
 16. The system of claim 13,wherein the processor is configured to identify the depth range byidentifying saturated pixels and adjacent pixels of the depth map. 17.The system of claim 13, wherein the processor is configured to performthe invalidating only on regions of the depth range that are alignedwith saturated pixels in the active brightness image that corresponds tothe depth map.
 18. The system of claim 13, wherein the depth camera andthe processor are implemented on separate devices.
 19. A devicecomprising: a depth camera configured to generate a depth map and acorresponding active brightness image of a scene; and, a bloom reductioncomputation component configured to detect blooming in the depth mapbased at least in part on saturated pixels of the active brightnessimage, identify a depth range of the saturated pixels, invalidate thedepth range of the saturated pixels from the depth map, and generateanother depth map that includes invalidated depths for the saturatedpixels.